code: def _init_config_vars():
      global _CONFIG_VARS
      _CONFIG_VARS = {}
      # Normalized versions of prefix and exec_prefix are handy to have;
      # in fact, these are the standard versions used most places in the
      # Distutils.
      _CONFIG_VARS["prefix"] = _PREFIX
      _CONFIG_VARS["exec_prefix"] = _EXEC_PREFIX
      _CONFIG_VARS["py_version"] = _PY_VERSION
      _CONFIG_VARS["py_version_short"] = _PY_VERSION_SHORT
      _CONFIG_VARS["py_version_nodot"] = _PY_VERSION_SHORT_NO_DOT
      _CONFIG_VARS["installed_base"] = _BASE_PREFIX
      _CONFIG_VARS["base"] = _PREFIX
      _CONFIG_VARS["installed_platbase"] = _BASE_EXEC_PREFIX
      _CONFIG_VARS["platbase"] = _EXEC_PREFIX
      _CONFIG_VARS["projectbase"] = _PROJECT_BASE
      _CONFIG_VARS["platlibdir"] = sys.platlibdir
      _CONFIG_VARS["implementation"] = _get_implementation()
      _CONFIG_VARS[
          "implementation_lower"
      ] = _get_implementation().lower()
      try:
          _CONFIG_VARS["abiflags"] = sys.abiflags
      except AttributeError:
          # sys.abiflags may not be defined on all platforms.
          _CONFIG_VARS["abiflags"] = ""
      try:
          _CONFIG_VARS["py_version_nodot_plat"] = sys.winver.replace(
              ".", ""
          )
      except AttributeError:
          _CONFIG_VARS["py_version_nodot_plat"] = ""
  
      if os.name == "nt":
          _init_non_posix(_CONFIG_VARS)
          _CONFIG_VARS["VPATH"] = sys._vpath
      if os.name == "posix":
          _init_posix(_CONFIG_VARS)
      if _HAS_USER_BASE:
          # Setting 'userbase' is done below the call to the
          # init function to enable using 'get_config_var' in
          # the init-function.
          _CONFIG_VARS["userbase"] = _getuserbase()
  
      # Always convert srcdir to an absolute path
      srcdir = _CONFIG_VARS.get("srcdir", _PROJECT_BASE)
      if os.name == "posix":
          if _PYTHON_BUILD:
              # If srcdir is a relative path (typically '.' or '..')
              # then it should be interpreted relative to the directory
              # containing Makefile.
              base = os.path.dirname(get_makefile_filename())
              srcdir = os.path.join(base, srcdir)
          else:
              # srcdir is not meaningful since the installation is
              # spread about the filesystem.  We choose the
              # directory containing the Makefile since we know it
              # exists.
              srcdir = os.path.dirname(get_makefile_filename())
      _CONFIG_VARS["srcdir"] = _safe_realpath(srcdir)
  
      # OS X platforms require special customization to handle
      # multi-architecture, multi-os-version installers
      if sys.platform == "darwin":
          import _osx_support
  
          _osx_support.customize_config_vars(_CONFIG_VARS)
  
      global _CONFIG_VARS_INITIALIZED
      _CONFIG_VARS_INITIALIZED = True
  
imports: import os
  import sys
  import threading
  from os.path import realpath
label_desc: Use image node_id 21 for calling a global function with example usage: _init_config_vars() without return types